Table 1 Threshold effect analysis of infertility duration (years) on the CPR
Outcome | Clinical pregnancy | ||
|---|---|---|---|
Model I (linear) | aOR | 95% CI | p value |
Linear effect | 0.950 | (0.910, 0.990) | 0.057 |
Model II (polyline) | aOR | 95% CI | p value |
Predicted threshold (K, infertility duration, years) | 5.0 | ||
Effect 1 (< K) | 0.978 | (0.916, 1.026) | 0.392 |
Effect 2 (> K) | 0.894 | (0.817, 0.991) | 0.043 |
variability of effectiveness | 0.926 | (0.808, 1.061) | 0.251 |
Logarithmic likelihood ratio test | 0.024 | ||